More than a billion Muslims observed the start of Ramadan on Monday, but in the besieged cities of Syria and Iraq residents were struggling with how to mark the holy month.
Islamic authorities across much of the world -- from the most populous Muslim-majority country Indonesia to Saudi Arabia, home to the faith's holiest sites -- announced the start of the fasting month with the sighting of the crescent moon.
Marking the divine revelation received by Islam's Prophet Mohammed, the month sees Muslim faithful abstain from eating, drinking, smoking and having sex from dawn to dusk.
They break the fast with a meal known as iftar and before dawn have a second opportunity to eat and drink during suhur. The month is followed by the Eid al-Fitr festival.
In Syria's second city Aleppo, divided between President Bashar al-Assad's forces and rebel fighters since 2012, residents of opposition-held eastern neighbourhoods despaired for the month ahead.
Many have grown accustomed to hardship after five years of war, but this year's Ramadan was expected to be especially difficult after recent fighting cut off the Castello Road -- the last supply route into their area.
"We can't gather together in the holy month like we always used to before the war," said Ahmad Aswad, a 35-year-old father of three in the eastern Salhin district.
"The cost of food has risen so much that it's really hard to even get a bite to eat," he said, his only hope for this Ramadan that unlike the holy month last year the city is not heavily bombed during the night.
In the Syrian city of Madaya, where some 40,000 people have been living under government siege for months, resident Mumina was preparing to break the fast with her husband using the little food aid the United Nations has managed to bring in.
"The food packages we receive are very bland, pulses and five cans of tuna per person. There's no pasta, no meat, no dairy. We tried to plant some vegetables but the land isn't good for planting now," the 32-year-old said.
"There's barely any food in the markets and whatever we find is so expensive that we can't buy it," she said, planning a simple meal of beans for Monday night.
In the Iraqi city of Fallujah, father-of-six Abu Mohammed al-Dulaimi also worried about how to provide food for his family during Ramadan.
Iraqi forces have tightened a siege around Fallujah as they press a major advance to retake the city from the Islamic State militant group.
An estimated 50,000 people are believed trapped inside, some being used as human shields by IS group, and the families left behind are often those who could not afford to leave.
"You have to get up at 5:00 in the morning and stand in line forever to pay 5,000 dinars ($4.50) for a kilo of tomatoes," said Dulaimi, contacted by AFP inside Fallujah.
"I can't even go there myself, I have to send someone, because you need to have a long beard and a short dishdasha," he said, referring to traditional robes which the militants insist should be worn shorter than usual in local custom.
In other parts of the Islamic world Muslims were preparing to mark Ramadan with extravagance.
In the wealthy Gulf states, hotels and restaurants were competing to offer the most luxurious meals.
At Dubai's sail-shaped landmark Burj al-Arab hotel, diners were being offered "an array of delectable traditional delicacies" at iftar meals for 400 Emirati dirhams ($110) per person.
In Indonesia, faithful spent the days leading up to Ramadan taking part in rituals, including visits to relatives' tombs and swims in springs infused with flowers.
Most in the country practise a moderate form of Islam and centuries-old, local beliefs are often fused with Muslim customs to create a particularly Indonesian brand of the faith.
Indonesia's conservative Muslim leaders regularly urge people not to partake in some of these rituals -- such as swimming in springs -- but the practices are deeply entrenched.
Hardline group the Islamic Defenders' Front (FPI) also threatened to launch raids on Indonesian nightspots that flout restrictions during Ramadan. In the past, the group has raided bars that are open later than they should be, seizing alcohol and throwing out customers.
"Please respect the holiness of Ramadan," Ja'far Shodiq, the group's deputy chairman, told AFP.
"The FPI is not against fun -- but sometimes fun can verge on immoral."
In China, the start of Ramadan was marked with the customary ban on civil servants, students and children in the mainly Muslim Xinjiang region taking part in the daytime fast.
China's ruling Communist party has for years banned government employees and minors from fasting in Xinjiang, home to the more than 10 million strong Uighur minority. It has also ordered restaurants to stay open.